The Qdrant collections use regulation_id (e.g. eu_2016_679) as the filter key,
not regulation_code (e.g. GDPR). Updated rag-constants.ts with correct qdrant_id
mappings from actual Qdrant data, fixed API to filter on regulation_id, and updated
ChunkBrowserQA to pass qdrant_id values.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>